Electric indicating mechanism for pressure-gages.



N0 MODEL.

J. P. ANDERSON.

ELECTRIC INDIO ATING MECHANISM FOR PRESSURE GAGES PATENTED NOV. 15, 1904APPLICATION FILED MAR. 16.1908.

UNITED STATEs Patented November 15, 1904.

JAMES P. ANDERSON, OF THE UNITED STATES NAVY.

ELECTRIC INDICATING MECHANISM FOR PRESSURE-GAGES.

SPECIFICATION forming part of Let rs Pa nt N0. 774,815, dated November15, 1904.

Application filed March 16, 1903. Serial No. 147,983. (No model.)

To all whom, it may concern.-

Be it known that I, JAMEs P. ANDERSON, a citizen of the -United States,in the United States Navy, have invented certain new and usefulImprovements in Electric Indicating Mechanism for Pressure-Gages, ofwhich the following is a specification.

My invention relates to electric indicating mechanism forpressure-gages.

My object is the provision of an electric indicating mechanism of simpleand improved construction whereby the indications of the needle orindicator on the pressure-gage will be accurately and instantaneouslyindicated electrically at any desired point.

In the practical application of the invention it is intended to be usedin connection with a steam or air pressuregage; and my object is toprovide in connection with the pressure-gage a resistance which will beincreased or diminished by contact of the indicator or needle accordingto fluctuations of the pressure, said resistance being in circuit with amilliampere-meter whose needle acts in response to fluctuations in thecurrent, the arrangement being such that the needle of themilliampere-meter will act synchronously.

with the needle or indicator of the pressuregage and indicate on thegraduations of the millianipere-meter the exact position of the needleof the pressure-gage. In this connection I desire it to be understoodthat the pres.- ent invention comprehends the utilization of thefluctuations in the current occasioned by the cutting in and out ofresistance by the pressure-gage needle to directly aifect the needle ofthe milliampere-meter as contradistinguished from those electric gageswhere magnets are employed to actuate through some mechanicalarrangement the needle of the meter.

Further objects are the provision of a novel form of combined needle andcontact on the pressure-gage which is adapted to make the contact on theface of the gage and at the same time give direct reading of theindication.

The invention is set forth in detail hereinafter and the novel featuresrecited in the appended claims.

In the accompanying drawings, Figure 1 illustrates the inventiongenerally, and Fig. 2 more particularly illustrates the circuitconnections.

The steam, air, or other pressure gage 1 may be of ordinary constructionand receive its pressure for actuation of its needle or indicator 2through the pipe 3. This gage has the usual graduations 1 on its facearranged in a circle, and arranged concentrically with these graduationsis the series of contact-plates 5, suitably insulated from the face ofthe gage, and each member is arranged radially in relation to thepivotal point of the needle 2, one contact member being provided foreach degree or graduation. The first contact member 5',representingzero, is dead; but beginning with the next contact member, 5, a seriesof resistances 6 is provided. all of said resistances being of equalresistance and joining adjacent contacts. The needle is provided with astraight contact tip or end 7, adapted to bear against the contacts 5and only of suificient width to bear on one contact or to bridge twoadjacent contacts. The needle also has an enlargedor open ring portion8, providing a peep-opening 9, into which projects the pointer 10 of theneedle. The reading on the gage can therefore be directly had, while atthe same time the needle serves as a contact-maker. From the lastcontact member 5 extends a circuit-wire 11, which connects with onebinding-post of a milliampere-meter 12, of any preferred constructionand having the coil 13, which through the fluctuations in the currentcontrols the movement of the needle 14, which travels over the scale 15.said scale being graduated in correspondence to the scale or gradnations of the gage. From the other binding-post of themilliampere-meter extends the circuit-wire 16, which leads to adouble-pole knife-switch 17 and thence to a fuse-box 18 and. to onefeeder or lead ofan ordinary feedcircuit 19. From the other wire of thelead 19 circuit-wire 20 extends to the fuse-box and thence to theknife-switch and to a thirty-twocandle-power incandescent lamp 21 andthence to the pivotal point of the needle 2. The

fuse-box prevents injury to the instruments, and the switch permitsthrowing them out of circuit, while the lamp can serve as anillumination for the readings and also that the device is in Workingorder. The resistance of the Wires between the pressure-gage and themilliampere-meter has to be taken into consideration, and themilliampere-meter is in practice constructed so as to register itshighest reading with athousand feet of No. 14 wire, (Brown & Sharpegage,) and if applied for use at shorter distances a wire with acorrespondingly-increased resistance must be installed. The lamp 21allows approximately one ampere to pass, thereby preventing sparking ofthe needle 2 on the contact-points.

Assuming that the gage is at zero and the contact portion 7 on the deadcontact 5, as the needle 2 is moved around by the pressure the contactend 7 travels over the contact 5 and successively cuts out theresistance until when upon the last contact 5 all the resistance of thepressure-gage is cut out. As the resistances 6 are thus successivelycutout the resistance of the circuit in which the milliampere-meter isincluded is lessened, and the needle 14 moves from left to right on thescale 15 in perfect synchronism with the movement of the needle 2 of thepressure-gage. Similarly as the needle 2 drops back on adecrease of thepressure more resistance will be cut in, and the needle 14: will dropback toward the Zero of the scale 15 in synchronism with the needle 2.It will be understood that the milliampere-meter can be placed at anydistance from the pressure-gage, so that the indication on thepressure-gage can be read Wherever the milliampere meter may be placed.

Having thus described my invention, What I claim as new, and desire tosecure by Letters Patent, is

1. In an electric indicating mechanism for electric gages, thecombination with a pressure-gage having a scale, of a pressure-actuatedpointer adapted to travel over said scale, a series of contactscorresponding to certain graduations of the scale and With Which thepointer contacts as it travels over said scale. resistances connectingadjacent contacts which are cut in or out as the pointer moves, anelectric indicator comprising a coil, a needle influenced by the coil, ascale corresponding to the scale of the pressure-gage and over which theneedle is adapted to travel, and a circuit and source of currentembracing the pointer and the coil and more or less of the resistancesaccording to the position of the pointer, whereby the needle of theelectrical indicator is made to move in synchronism with the pointer ofthe pressure-gage by the fluctuations of the current in the coil causedby cutting in and out of the resistances of the gage.

2. In an electric indicating mechanism for pressure-gages, thecombination with a pressure-gage having a circularly-a1ranged scale, ofa series of circularly-arranged contacts on the gage corresponding innumber to the graduations of the scale, equal resistances connectingadjacent contacts, a pressure-actuated pivoted pointer adapted .toindicate on the scale and also to make contact with the contactssuccessively, an electrical indicator having a circularly-arranged scalecorresponding to the scale of the pressure-gage, and having a coil and aneedle influenced directly by the fluctuations of the current in thecoil, a circuit embracing the pointer and the coil of the electricalindicator and more or less of the resistances according to the positionof the pointer, and an electric test-light in said circuit, Whereby theneedle of the electrical indicator moves in synchronism with the pointerof the pressure-gage and the test-light is continuously illuminatedduring the operation to continuously indicate that the circuitconditions are correct.

In testimony whereof I hereunto aflix my signature in presence of twoWitnesses;

JAMES P. ANDERSON.

Witnesses:

D. K. STARBUOK, MARIE HUSE KIDDER.

